There's a hole at the center of "Turn It Up," a grim and violent drama set against New York's hip-hop recording world. The hole is caused by the film's two stars, hip-hop recording artists Prakazrel "Pras" Michel and Ja Rule.

In "Turn It Up," which opens today, Pras and Ja Rule play Diamond and Gage, a struggling rapper and his loose-cannon manager. These men know this terrain as well as anybody -- Pras was one third of the Fugees; Rule has his own hip- hop career -- but unlike Ice Cube, Tupac Shakur or other rappers who successfully segued to movies, they haven't got a shred of acting talent.

Pras and Rule look good, and handle their guns smoothly in the movie's elaborate shootouts, but there's nothing in their eyes, no spark or passion. That's a big liability in a movie that tries to explore ambition, artistry and the fierce desire to be recognized and respected.

Buddies since they were 6, Diamond and Gage form an alliance to break into the music industry. On the side, they deliver drugs for Mr. B, a menacing British drug czar played by Jason Statham of "Lock, Stock and Two Smoking Barrels." Diamond wants to go legit and quit dealing, but when recording-studio bills mount, Gage goes behind his back and tries a desperate solution.

The other elements seem as though they were sampled at random from a dozen movies of this ilk: a girlfriend for Diamond (Tamala Jones) whose two functions are to get pregnant and complain, a devoted mama (Elain Graham), a deadbeat dad (Vondie Curtis Hall) who drifts back to Diamond and an oil- dripping record exec (John Ralston) who purrs, "Your manager tells me your rap is hot."

This is the first feature directed by Robert Adetuyi, who also wrote the unfortunate screenplay. Witness this gem, spoken by Pras when his girlfriend gripes that he's rarely at home: "Why do you think the first thing they do when a baby comes out of the womb is cut the cord? 'Cause a man has to be free!"

Hubert Taczanowski's dark and moody photography is small compensation for a bad movie. "Turn It Up" never comes alive, in fact, until Pras and Ja Rule go onstage, as they do in real life, to deliver some scorching hip-hop. In those moments, they're wired with the conviction, timing and raw power that their acting lacks.